code: def test_SeparateObservations(self) -> None:
      obs_arm_name = "0_0"
      obs = Observation(
          features=ObservationFeatures(parameters={"x": 20}),
          data=ObservationData(
              means=np.array([1]),
              covariance=np.array([[2]]),
              metric_names=["a"],
          ),
          arm_name=obs_arm_name,
      )
      obs_feats, obs_data = separate_observations(observations=[obs])
      self.assertEqual(
          obs.features, ObservationFeatures(parameters={"x": 20})
      )
      self.assertEqual(
          obs.data,
          ObservationData(
              means=np.array([1]),
              covariance=np.array([[2]]),
              metric_names=["a"],
          ),
      )
      with self.assertRaises(ValueError):
          recombine_observations(
              observation_features=obs_feats, observation_data=[]
          )
      with self.assertRaises(ValueError):
          recombine_observations(
              observation_features=obs_feats,
              observation_data=obs_data,
              arm_names=[],
          )
      new_obs = recombine_observations(
          obs_feats, obs_data, [obs_arm_name]
      )[0]
      self.assertEqual(new_obs.features, obs.features)
      self.assertEqual(new_obs.data, obs.data)
      self.assertEqual(new_obs.arm_name, obs_arm_name)
      obs_feats, obs_data = separate_observations(
          observations=[obs], copy=True
      )
      self.assertEqual(
          obs.features, ObservationFeatures(parameters={"x": 20})
      )
      self.assertEqual(
          obs.data,
          ObservationData(
              means=np.array([1]),
              covariance=np.array([[2]]),
              metric_names=["a"],
          ),
      )
  
imports: import json
  from unittest.mock import Mock, PropertyMock
  import numpy
  import pandas
  from ax.core.arm import Arm
  from ax.core.base_trial import TrialStatus
  from ax.core.batch_trial import BatchTrial
  from ax.core.data import Data
  from ax.core.generator_run import GeneratorRun
  from ax.core.map_data import MapData, MapKeyInfo
  from ax.core.observation import Observation, ObservationData, ObservationFeatures, observations_from_data, observations_from_map_data, recombine_observations, separate_observations
  from ax.core.trial import Trial
  from ax.utils.common.testutils import TestCase
label_desc: Use image node_id 14 for calling the ObservationsTest obj's underlying member method code with example usage: obj.test_SeparateObservations() without return types